Research On Design And Evaluation Of Surface Micromachined MEMS Devices Based On Solid Model

A big challenge to the rapid development of MEMS (Micro Electromechanical Systems) devices is the lack of intuitive and effective MEMS design methods. In order to enable designers to design complex MEMS devices easily, quickly and without errors, researchers have begun to investigate structured design methods for MEMS in recent years, aiming at separating the design of MEMS from their process planning and fabrication. In this dissertation, a novel methodology for the design and evaluation of surface micromachined MEMS devices is presented. With this methodology, in order to design a MEMS device, the designer first creates its solid model using a traditional CAD system, and the process model of the MEMS device including mask layout and fabrication process is then generated on the basis of the solid model. The main advantages of the methodology are the designer can concentrate on function and shape design of MEMS devices and complex MEMS devices can be modeled in MEMS CAD system.The main contributions of the dissertation are presented as follows:(1) A framework for design and evaluation of surface micromachined MEMS devices based on solid model. In the framework, the generation of the process model for fabricating a surface micromachined MEMS device is devided into two steps: layer modeling and mask synthesizing based on the layer model.(2) An approach to layer modeling based on the solid model for surface micromachined MEMS. In this approach, process features are defined and classified for surface micromachining, which are automatically recognized from the solid model of a surface micromachined MEMS device. Then the layer model is automatically generated on the basis of the recognized process features. At last, for the multi-layer etch which etches through more than one layer with the same material property until a different material reached, an algorithm of correcting the layer model is proposed based on the property of the multi-layer etch.(3) A systematic method of evaluating and improving layer model. Firstly, the manufacturability of layer model is analyzed, which includes the releasability of sacrificial material, the manufacturability of fabrication order, the manufacturability of deposit, the contact of all layers and the manufacturability of etching, etc., and the evaluation algorithms are developed accordingly. Secondly, redesign suggestions are generated based...